This invention is concerned with a method of deadening sound in metallic panels and particularly deadening sound of the components of vehicles, especially under hood sound deadening in automobiles.
In order to prevent the passage of noise especially from beneath the hood of a vehicle into the passenger compartment it has been conventional practice in recent years to secure to a layer of fiberglass material in sheet form on the under side of an automobile hood. Apart from now perceived potential problems in working with fiberglass, the layer of fiberglass required was relatively heavy, typically in the range 1.0 to 1.5 kg/m.sup.2. It sagged and tended to tear fairly easily, especially where it was attached to the metal. Moreover, although the sound deadening qualities of fiberglass material were sufficient to meet the specifications laid down, the material had a number of disadvantages, especially in that it did not mold readily to the shape of the under side of the hood.